In general, an electric compressor provided for compressing a coolant and circulating the compressed coolant in a circuit is driven by a DC motor coupled to the compressor, so as to achieve the effects of compressing and circulating the coolant. Different internal compression mechanisms include various models of rotary compressors, scroll compressors and screw compressors.
Wherein, the scroll compressor has the issue of a relatively difficult manufacturing process and incurs a high cost. Although both rotary compressors and screw compressors complete a compression process by changing the volume of a compression chamber, the rotary compressors adopt a simple compression method and skillfully avoid the problems including the deviation of the screw compressors caused a force exertion in an axial direction, the clearance volume, and the internal leakage, so as to improve the reliability and performance of the equipments and accomplish a relatively higher market share.
In a rotary compressor as shown in FIG. 1, an eccentric shaft 11 is installed to the center of the motor rotor 12, such that when the eccentric shaft 11 rotates with the motor rotor 12 to turn around in a housing 13, the eccentric shaft 11 and a cylinder wall form a series of compression chambers of different volumes to achieve the effect of compressing the coolant progressively. In the operation of the rotary compressors, the cylinder is compressed by an eccentric method, so that there are issues of having vibrations and increasing the torque.
Although some motor rotors 12 of the conventional rotary compressors comes with a weight 14 to inhibit the vibration caused by the eccentric rotation, yet when the eccentric shaft 11 is installed to the motor rotor 12, the level of difficulty of setting the center and direction of the eccentric shaft 11 is increased. Therefore, it is a main subject for related manufacturers to design and develop a mechanism for setting the center and the direction between the eccentric shaft and the motor rotor quickly to improve the assembling quality and production capacity of the rotary compressors.